This invention relates to metal picture frames. More particularly, this invention relates to a picture frame of the type comprising extruded aluminum frame sections which are mitred and locked together by means of L-shaped, double plated corner pieces.
A picture frame in common use today is made of extruded aluminum frame sections, each of which includes a locking channel into which the legs of an L-shaped corner piece can be inserted. The corner piece includes two similarly shaped plates which are sometimes referred to as a tapped (threaded) upper plate and a backing plate. The tapped plate includes a threaded opening in each leg for receiving a screw which is accessible through an elongated slot in the back of a frame section. By tightening the screws the tapped plate and backing plate are forced apart thereby clamping the plates against opposing surfaces of the locking channels of two adjacent frame sections to lock the two frame sections together. The backing plate may be unconnected to the tapped plate, or the plates may be held together by means of an elastomeric adhesive applied at the junction of the legs which form the xe2x80x9cLxe2x80x9d. The tapped plate is also known as a locking plate.
When a framer assembles a frame. the two screws in the corner piece are tightened successively. Very often, after the first screw has been tightened with the frame sections carefully aligned, tightening of the second screw will result in slight movement of one frame section relative to the other. When this happens, it is necessary to release the lock and then retighten the screws, hopefully without again losing the alignment.
The object of this invention is to provide a corner piece of the type described in which the likelihood of misaligning the frame sections during attachment of the corner piece is substantially reduced.
In addition to the time saved by eliminating the need to readjust the frame sections by enabling the frame corners to be tightened in a single step, the time required to assemble a frame is reduced. This is a substantial benefit to large volume framers.
A picture frame comprises mitred metal frame sections joined together at each corner by a double plated corner piece. The corner piece includes an L-shaped locking plate, a backing plate, and a single member which engages with the locking plate and is adapted to bear against the backing plate. The single member is preferably positioned at the junction of the two legs of the respective plates and is accessible through an opening in the back of the frame sections at their mitred junction. The single member may comprise a screw or cam, both of which function to separate the two plates thereby locking the adjacent frame sections together.